The present disclosure relates to methods and materials for making a low bulk density proppant capable of providing permeability at subterranean pressures.
Oil and natural gas are produced from wells having porous and permeable subterranean formations. The porosity of the formation permits the formation to store oil and gas, and the permeability of the formation permits the oil or gas fluid to move through the formation. Permeability of the formation is essential to permit oil and gas to flow to a location where it can be pumped from the well. Sometimes the permeability of the formation holding the gas or oil is insufficient for economic recovery of oil and gas. In other cases, during operation of the well, the permeability of the formation drops to the extent that further recovery becomes uneconomical. In such cases, it is necessary to fracture the formation and prop the fracture in an open condition by means of a proppant material or propping agent. Such fracturing is usually accomplished by hydraulic pressure, and the proppant material or propping agent is a particulate material, such as sand, glass beads or ceramic particles (all of which can be referred to as “proppant”), which are carried into the fracture by means of a fluid or gel (both of which can be referred to as “fracture fluid”). As the density of the proppant decreases, the fracture fluid used to carry the proppant into the fracture can have lower viscosity, which reduces the cost of the fracture fluid as well as reduces what is referred to as “gel damage”. Gel damage is caused by viscous fracture fluid which remains in the formation and blocks flow of gas or oil to the well bore. Additionally, as the density of the proppant decreases, it becomes easier and cheaper to pump the proppant into the fracture, and the proppant can get carried further into the fracture which will increase the oil or gas production for the well.